/*
 *
 * Copyright (c) 2006-2011 Sam Collett (http://www.texotela.co.uk)
 * Dual licensed under the MIT (http://www.opensource.org/licenses/mit-license.php)
 * and GPL (http://www.opensource.org/licenses/gpl-license.php) licenses.
 *
 * Version 1.3.1
 * Demo: http://www.texotela.co.uk/code/jquery/numeric/
 *
 */
(function($) {
	/*
	 * Allows only valid characters to be entered into input boxes.
	 * Note: fixes value when pasting via Ctrl+V, but not when using the mouse to paste
	 * side-effect: Ctrl+A does not work, though you can still use the mouse to select (or double-click to select all)
	 *
	 * @name numeric
	 * @param config { decimal : "." , negative : true }
	 * @param callback A function that runs if the number is not valid (fires onblur)
	 * @author Sam Collett (http://www.texotela.co.uk)
	 * @example $(".numeric").numeric();
	 * @example $(".numeric").numeric(","); // use , as separater
	 * @example $(".numeric").numeric({ decimal : "," }); // use , as separator
	 * @example $(".numeric").numeric({ negative : false }); // do not allow negative values
	 * @example $(".numeric").numeric(null, callback); // use default values, pass on the 'callback' function
	 *
	 */
	$.fn.numeric = function(config, callback) {
		if( typeof config === 'boolean') {
			config = {
				decimal : config
			};
		}
		config = config || {};
		// if config.negative undefined, set to true (default is to allow negative numbers)
		if( typeof config.negative == "undefined")
			config.negative = true;
		// set decimal point
		var decimal = (config.decimal === false) ? "" : config.decimal || ".";
		// allow negatives
		var negative = (config.negative === true) ? true : false;
		// callback function
		var callback = typeof callback == "function" ? callback : function() {
		};
		// set data and methods
		return this.data("numeric.decimal", decimal).data("numeric.negative", negative).data("numeric.callback", callback).keypress($.fn.numeric.keypress).keyup($.fn.numeric.keyup).blur($.fn.numeric.blur);
	}

	$.fn.numeric.keypress = function(e) {
		// get decimal character and determine if negatives are allowed
		var decimal = $.data(this, "numeric.decimal");
		var negative = $.data(this, "numeric.negative");
		// get the key that was pressed
		var key = e.charCode ? e.charCode : e.keyCode ? e.keyCode : 0;
		// allow enter/return key (only when in an input box)
		if(key == 13 && this.nodeName.toLowerCase() == "input") {
			return true;
		} else if(key == 13) {
			return false;
		}
		var allow = false;
		// allow Ctrl+A
		if((e.ctrlKey && key == 97 /* firefox */) || (e.ctrlKey && key == 65) /* opera */)
			return true;
		// allow Ctrl+X (cut)
		if((e.ctrlKey && key == 120 /* firefox */) || (e.ctrlKey && key == 88) /* opera */)
			return true;
		// allow Ctrl+C (copy)
		if((e.ctrlKey && key == 99 /* firefox */) || (e.ctrlKey && key == 67) /* opera */)
			return true;
		// allow Ctrl+Z (undo)
		if((e.ctrlKey && key == 122 /* firefox */) || (e.ctrlKey && key == 90) /* opera */)
			return true;
		// allow or deny Ctrl+V (paste), Shift+Ins
		if((e.ctrlKey && key == 118 /* firefox */) || (e.ctrlKey && key == 86)/* opera */ || (e.shiftKey && key == 45))
			return true;
		// if a number was not pressed
		if(key < 48 || key > 57) {
			var value = $(this).val();
			/* '-' only allowed at start and if negative numbers allowed */
			if(value.indexOf("-") != 0 && negative && key == 45 && (value.length == 0 || ($.fn.getSelectionStart(this)) == 0))
				return true;
			/* only one decimal separator allowed */
			if(decimal && key == decimal.charCodeAt(0) && value.indexOf(decimal) != -1) {
				allow = false;
			}
			// check for other keys that have special purposes
			if(key != 8/* backspace */ && key != 9/* tab */ && key != 13/* enter */ && key != 35/* end */ && key != 36/* home */ && key != 37/* left */ && key != 39/* right */ && key != 46 /* del */
			) {
				allow = false;
			} else {
				// for detecting special keys (listed above)
				// IE does not support 'charCode' and ignores them in keypress anyway
				if( typeof e.charCode != "undefined") {
					// special keys have 'keyCode' and 'which' the same (e.g. backspace)
					if(e.keyCode == e.which && e.which != 0) {
						allow = true;
						// . and delete share the same code, don't allow . (will be set to true later if it is the decimal point)
						if(e.which == 46)
							allow = false;
					}
					// or keyCode != 0 and 'charCode'/'which' = 0
					else if(e.keyCode != 0 && e.charCode == 0 && e.which == 0) {
						allow = true;
					}
				}
			}
			// if key pressed is the decimal and it is not already in the field
			if(decimal && key == decimal.charCodeAt(0)) {
				if(value.indexOf(decimal) == -1) {
					allow = true;
				} else {
					allow = false;
				}
			}
		} else {
			allow = true;
		}
		return allow;
	}

	$.fn.numeric.keyup = function(e) {
		var val = $(this).value;
		if(val && val.length > 0) {
			// get carat (cursor) position
			var carat = $.fn.getSelectionStart(this);
			// get decimal character and determine if negatives are allowed
			var decimal = $.data(this, "numeric.decimal");
			var negative = $.data(this, "numeric.negative");

			// prepend a 0 if necessary
			if(decimal != "") {
				// find decimal point
				var dot = val.indexOf(decimal);
				// if dot at start, add 0 before
				if(dot == 0) {
					this.value = "0" + val;
				}
				// if dot at position 1, check if there is a - symbol before it
				if(dot == 1 && val.charAt(0) == "-") {
					this.value = "-0" + val.substring(1);
				}
				val = this.value;
			}

			// if pasted in, only allow the following characters
			var validChars = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, '-', decimal];
			// get length of the value (to loop through)
			var length = val.length;
			// loop backwards (to prevent going out of bounds)
			for(var i = length - 1; i >= 0; i--) {
				var ch = val.charAt(i);
				// remove '-' if it is in the wrong place
				if(i != 0 && ch == "-") {
					val = val.substring(0, i) + val.substring(i + 1);
				}
				// remove character if it is at the start, a '-' and negatives aren't allowed
				else if(i == 0 && !negative && ch == "-") {
					val = val.substring(1);
				}
				var validChar = false;
				// loop through validChars
				for(var j = 0; j < validChars.length; j++) {
					// if it is valid, break out the loop
					if(ch == validChars[j]) {
						validChar = true;
						break;
					}
				}
				// if not a valid character, or a space, remove
				if(!validChar || ch == " ") {
					val = val.substring(0, i) + val.substring(i + 1);
				}
			}
			// remove extra decimal characters
			var firstDecimal = val.indexOf(decimal);
			if(firstDecimal > 0) {
				for(var i = length - 1; i > firstDecimal; i--) {
					var ch = val.charAt(i);
					// remove decimal character
					if(ch == decimal) {
						val = val.substring(0, i) + val.substring(i + 1);
					}
				}
			}
			// set the value and prevent the cursor moving to the end
			this.value = val;
			$.fn.setSelection(this, carat);
		}
	}

	$.fn.numeric.blur = function() {
		var decimal = $.data(this, "numeric.decimal");
		var callback = $.data(this, "numeric.callback");
		var val = this.value;
		if(val != "") {
			var re = new RegExp("^\\d+$|\\d*" + decimal + "\\d+");
			if(!re.exec(val)) {
				callback.apply(this);
			}
		}
	}

	$.fn.removeNumeric = function() {
		return this.data("numeric.decimal", null).data("numeric.negative", null).data("numeric.callback", null).unbind("keypress", $.fn.numeric.keypress).unbind("blur", $.fn.numeric.blur);
	}
	// Based on code from http://javascript.nwbox.com/cursor_position/ (Diego Perini <dperini@nwbox.com>)
	$.fn.getSelectionStart = function(o) {
		if(o.createTextRange) {
			var r = document.selection.createRange().duplicate();
			r.moveEnd('character', o.value.length);
			if(r.text == '')
				return o.value.length;
			return o.value.lastIndexOf(r.text);
		} else
			return o.selectionStart;
	}
	// set the selection, o is the object (input), p is the position ([start, end] or just start)
	$.fn.setSelection = function(o, p) {
		// if p is number, start and end are the same
		if( typeof p == "number")
			p = [p, p];
		// only set if p is an array of length 2
		if(p && p.constructor == Array && p.length == 2) {
			if(o.createTextRange) {
				var r = o.createTextRange();
				r.collapse(true);
				r.moveStart('character', p[0]);
				r.moveEnd('character', p[1]);
				r.select();
			} else if(o.setSelectionRange) {
				o.focus();
				o.setSelectionRange(p[0], p[1]);
			}
		}
	}
})(jQuery);
